Do you use autoupdate-5.x? Also, obsoletes tags have been supported
for a
long time now, I think..
Newer versions handle the more difficult cases with "autoinfo" files which
include all the information (such as epochs etc.).
Autoupdate also includes perl-RPM bindings which make it a bit more
robust.
Last time I had heard the perl-rpm bindings weren't being maintained
much anymore. Yum is in python so it can take advantage of red hat
maintaining the python bindings for its own software (anaconda, up2date,
redhat-config-packages)
-sv